STEROLS AND POLYAMINES IN IPT-TRANSFORMED TOBACCO PLANTS

Free sterol and free polyamine contents were determined in the apex an d the leaves of control and Pssu-ipt transformed tobacco (Nicotiana ta bacum L. cv. Petit Havana SR1). The older leaves of ipt-transformed pl ants contained a much higher putrescine (put) content than those of co ntrol SR1 plants, whereas no significant differences for spermidine (s pd) or spermine (spm) were found between control and ipt plants. Putre scine content corresponded well with endogenous cytokinin (free-bases) content and with ornithine- and ornithine-decarboxylose (ODC and ADC) activities. Plants transformed with ipt were characterized by a highe r sterol content in the leaves and by a delay in the increase in the s tigmasterol/sitosterol ratio that occurs from the upper to the lower l eaves. Copyright (C) 1997 Elsevier Science Ltd.